As winter begins to tighten its icy grip on Afghanistan, millions of Afghans face cold and starvation, but for many there seems little prospect of escape.

Roberta Cohen, co-director of the Brookings Institution Project on Internal Displacement, says that in the current uncertain situation, no one knows for certain how many Afghans are homeless. But she says it is widely assumed the number is many times higher than the one million Afghans displaced before September 11.

"There are no estimates how many internally displaced persons are there now. One doesn't really know," she said. "I've heard estimates running up to several million from the one million before September 11. But now people are on the run from bombing, they're on the run from conflict, they're on the run from starvation. So that we really don't know the numbers at this point."

Speaking to a congressional committee Thursday, Andrew Natsios, director of the U.S. government's Agency for International Development, said the problem goes much farther back than September 11. After three successive years of drought and famine, he says, most Afghans have exhausted what little they have.

"People who can deal with one year of a crop loss by using their family assets or using their animals, after three years, they have nothing left. And that's exactly where Afghanistan is right now," he said. "Families that had three or four hundred cows or goats or sheep five years ago have three or four left, and they're in emaciated condition. Farmers who planted crops for three years now, in 18 of the 29 provinces, there's been a complete crop failure. So if you're poor to begin with, and you've had that happen to you, the consequence is, the people have no more coping mechanisms."

Now they have a war on top of famine.

The United States began dropping packets of food rations to Afghans, when the bombing campaign began. But the food drops have been to areas outside the bombing zones. Aid workers say Afghans need not only more comprehensive food aid, but blankets and shelter to help them through the cruel Afghan winter.

Andrew Wilder, Afghanistan and Pakistan director for the Save the Children Foundation, said by phone from Islamabad that large-scale supplies of food must be trucked in. "So I think that as long as we can truck food in, that is by far the preferred option to get large-scale assistance into Afghanistan," he said. "I think that when that option, if we no longer have that option, then we do need to look at issues of airdrops and airlifts. But I don't think we reached that point quite yet."

His organization, for example, buys food basics from traders in Turkmenistan and then trucks them in.

There have been reports of Taleban fighters stealing or confiscating food supplies from the United Nations and private relief agencies. Mr. Natsios speaks of what he calls "exceptionally aggressive" harassment of some relief workers by the Taleban.

Roberta Cohen of the Brookings Institution says that, to the surprise of many people, Iran has been the most cooperative in letting aid get through to the displaced people in Western Afghanistan. But there remain many remote, inaccessible areas, she says, where hunger or cold will claim lives this winter even if they are way out of the firing line.